Located in Tsukiji is the Tsukiji Fish Market which is the biggest wholesale fish and seafood market in the world. The market opens at 3 am for trading where over 400 different types of seafood exchange hands.
Tuna auctions take place at about 05:20 and end at 07:00-ish. Many gaijin tourists used to come to watch the auctions but due to a few lame individuals who cause trouble, tourists were banned from watching the auctions. I think they do allow tourists to go in depending on the season under supervision by security guards though.
The cloth that hangs from the window is called Noren . They are usually hung from windows and doorways. They have slits in them to allow easy passage or viewing. Traditionally they have been used to keep out the sun, wind and dust. I remember buying some when I first came to Japan and put it up in my kitchen doorway back in London - its still there ^^;
Before you enter the park, you can pick up a portable terminal which contains voice and video that you can watch as you walk around the gardens. Depending on your location, you will be read or shown some history of the gardens.
The loan of the terminal is free and they have 50 sets available.